In their conflict with Russia, Ukrainians are almost universally seen as the good guys. At Monday's United Nations Security Council meeting, no one backed Russia's description of its military intervention in the Crimea as an attempt to defend Russian citizens and pro-Russian Ukrainians. Russian President Vladimir Putin was openly lying when he said the Crimea was now controlled by local "self-defense forces": Eyewitness reports clearly indicate that Russian troops have seized the peninsula without a single shot but in clear violation of international treaties.

That makes it hard to play the devil's advocate, but experience tells me that there are no conflicts in which one side is entirely in the right. Hyperbole aside, Putin and his people have made several valid points about the situation in Ukraine.

De jure, Putin is right when he says Viktor Yanukovych is still president of Ukraine. The Ukrainian constitution describes only three ways in which a president can lose his powers: Death, resignation and a convoluted impeachment procedure that requires, at the end, the votes of three-quarters of parliament members. Yanukovych is alive, he has not resigned and the impeachment procedure was not followed. Instead, he was removed with a parliamentary resolution saying that he had "disengaged" from power. The unconstitutional move gives Putin grounds to say Ukraine has experienced a coup d'etat.

The Russian descriptions of violence during the Ukrainian revolution are also, to an extent, true. "Government buildings were seized and burned, police were attacked, arms warehouses were robbed and officials in the regions humiliated," Russian representative Vitali Churkin told the Security Council. "Downtown Kiev and many cities in the west of Ukraine were seized by armed radical nationalists under extremist, anti-Russian and anti-Semitic slogans."

Indeed, protesters seized government buildings throughout the nation, and I have been to some of them in Kiev. They set fire to the head office of Yanukovych's Regions Party, killing an engineer who worked in it. In Lvov in Western Ukraine, they stormed a garrison and indeed seized control of its arms warehouses, although local media reported the stockpiles were immediately sealed. The governor of the western region of Volyn was handcuffed to the stage of a protest rally in Lutsk.

It is true, too, that buildings and whole areas of Ukrainian cities were occupied by radicals. I have not seen a single anti-Semitic slogan, but nationalist and anti-Putin ones were common. In fact, the so-called self-defense forces, formed by the protesters to drive off police attacks, are still very much in evidence and, to some extent, in control. On a trip to Kiev last weekend, I saw a scruffy volunteer security checking travelers' papers against a crumpled list at the Zhulyany airport, trying to make sure no Yanukovych cronies got away. I saw people from several different self-defense "hundreds" patrolling parts of Yanukovych's opulent former residence, Mezhihirya, which now serves as a public park and museum of his corrupt rule.

Some of these vigilantes were intellectuals without any inclination toward arbitrary violence. I was given a tour of Mezhihirya by a young, soft-spoken geneticist, and another self-defense "soldier" gave an impromptu recital on Yanukovych's white grand piano. I also saw, however, people in camouflage carrying Uzis and Kalashnikovs whose paths I would not like to cross in a dark alley. There is little coordination among the "hundreds," and there have been reports of raids against businesses, theft of nationalized Mezhirirya property and other unseemly deeds by people claiming to belong to the self-defense forces.

Throughout the Kiev protests, I have visited the city many times and never tried to conceal my Russian citizenship. Besides, I speak Russian with a Moscow accent which locals easily recognize, and my Ukrainian is almost non-existent. Nonetheless, protesters, even radical nationalists, have never been less than welcoming. My Ukrainian friends say they feel safer in a city patrolled by the self-defense than by Yanukovych's notoriously corrupt and unfriendly cops. That said, it is not an entirely normal situation when police are available only if you dial 112: It may be too late to make the call if vigilantes in camouflage find your name on some list.

It is also true that Russian speakers in Ukraine's southeastern regions fear the Ukrainian nationalists who have seized power in Kiev and formed the current government. To many of them, Stepan Bandera, the radical nationalists' icon who joined forces with the Nazis to fight the Russian army during World War II, but then fell out of favor with the Third Reich's leaders, is a hate figure. As the journalist Yelena Shkarpova, a supporter of the revolution but a native of eastern Ukraine, wrote on Facebook: "My classmates will never understand the mess in downtown Kiev. People in Donetsk will never recognize Bandera as a fighter for Ukrainian independence. This is where logic does not work because everybody has his own logic. It's like religion."

Putin is right when he says people who do not subscribe to the nationalist "religion" are underrepresented in the post-revolutionary government of acting president Oleksandr Turchynov and prime minister Arseniy Yatsenyuk. The new authorities have also appointed representatives of the former opposition as governors to regions such as Kharkov and Donetsk, which backed Yanukovych and his party in recent elections.

Putin stepped up activity in the Crimea after the Ukrainian parliament repealed a law that recognized Russian as a "regional language" in areas where it is the mother tongue for more than 10 percent of the population. Turchynov vetoed the repeal, but the wrong signal had already been sent. One of Ukraine's most talented politicians, Lvov mayor Andriy Sadoviy, tried to soften its effect with a heartfelt address to eastern Ukrainians, delivered in excellent Russian, but it is not Sadovy who runs the government.

I cannot even speak about any of this with many of the people I know in Ukraine, because they immediately brand me a Putin sympathizer and a Russian imperialist. Wars, or near-wars, brainwash people on both sides. I do, however, know people in Kiev who believe that it is time to disarm the militias and get them off the streets; that Russian should be recognized as an official language alongside Ukrainian; that the eastern regions, including the Crimea, should be given more autonomy; that it might be a good idea to elect and not appoint governors.

Even these people, however, find it hard to discuss political inclusiveness and democracy while a foreign power controls part of the country and continues threatening to invade the rest of it. There is no guarantee that Putin will pull out if the rights of the Russian-speaking easterners are transparently assured. Having just deposed a president who would not listen to them, Ukrainians are not sure it is possible to negotiate with Putin. So many are grimly preparing to fight him, too.

Neither side wants to work toward a face-saving compromise. As a result, Putin is now fighting a public relations war against the entire West, and Ukrainians are developing a siege mentality that undermines democratic governance and fills media with as much virulent propaganda and disinformation as Kremlin-controlled Russian TV carries.

This is a situation that badly needs a strong mediator.

Leonid Bershidsky

Leonid Bershidsky writes on Russia, Europe and technology for Bloomberg View. Follow him on Twitter at @Bershidsky.